Transmission synchronizer



Nov.. 19, 1940. B. A. BARR TRANSMI S S ION SYNCHRONI ZER Filed-oct. 25, 1959 NN QN Patented Nov. 19, 1940 I UNITED STATES PATENT OFFICE f 2,221,901 TRANSMISSION sYNcmtoNrzEn Bruce A. Barr, Muncie, Ind., assignor to Borg- Warner Corporation, Chicago, Ill., avcorpora-f tion of Illinois Appuoation october 25, 1939, ysonal No. 301,129 9 claims. (01.192-53) the medium of a movable positive drive. or jawclutch element, drivingly associated with one ofv said members andy adapted to be shifted-axially into clutching engagement with a complementary liaw clutch element drivingly associated'withv the other of said members. 'I'he invention is particularly directed to synchronizing transmissions of the type wherein the synchronizing means comprises friction clutch elements drivingly associated with the respective torque transmitting members, one of said elements being adapted to be moved axially into engagement with the other in thc initial stage of shifting of the movable .law clutch element through the medium of a thrust bar or a plurality of thrust bars having.

axial thrust transmitting engagement with the movable jawclutch element and the movable 2li` friction clutch element'respectively. The invention has as one of its objects, to

simplify and reduce the expense of manufacture o of a synchronizing transmission of the type outlined above. It has this object particularly in connection with the provision of resilient means for urging the thrust bars radially outwardly to establish the thrust receiving engagement with the interior of the movable jaw clutch sleeve, such resilient means being in the form of expander rings adapted to simultaneously engage all of the thrust bars.

In previous synchronizers of this general type, the synchronizer rings have been provided with axially opening notches receiving the ends of the thrust bars and thereby forming oscillatory lost motion connections between the rings and the torque transmitting member with whichthey are associated, such lost motion connections providing for biasing of the synchronizer rings in blocking relation to the shiftable jaw clutch sleeve. whereby to restrain the axial advance of j the sleeve into positive clutching engagement with its cooperating clutch element until synchronlzatlon has been attained.

The present invention contemplates an arrangement wherein the weakening effect of such.

axially opening notches in the synchronizer rings is eliminated., and the rings are of uniform cross-sectional area throughout their circumferential extent, and aims to provide a substitute for the formerly employed lost motion connection which does not increase the expensey of manufacture of the synchronizer.

Other objects, the advantagesand uses of the invention will become more apparent after read- 5 ingthe following specification and claims, and

after consideration of the drawing forming a part of the specification, wherein:

Fig. lis an axial sectional view of a transmission synchronizerembodying the invention; -10

Fig. 2 is a transverse sectional view thereof taken as indicated by the line 2-2 lof Fig.' l;

Fig. 3 is-a plan view ofthe same with portions, removed to disclose the interior, taken asindicated by the line 3-3vof Fig. 1; and 15 Fig. 4 is an axial sectional view taken as indicated by the line 4-4 of Fig. 2.` Y

As an example of one form in which the invention may be embodied, I have shown inthe drawing a transmission synchronizer including a 20 pair of aligned torque transmitting members III and II, the forward end of the member II being piloted,` as at I2,.in-the rear end of the member I0. The member I0 may be the driving shaft of` a conventional automobile transmission, and the 25 t member, II the driven shaftof such a transmis- I sion. I4 by means of which it is secured to the splined region l5 of the shaft II and is retained in an axially fixed position yby means of retaining rings 30 I6 and I1 recessed into the splined'region I5.

A positive drive yconnection is adapted to be y established between the torque .transmitting members I0 and I I or between a reduction geared torque transmitting `member I8` and the member-35 I I, by means of an axially movablev positive drive or jaw clutch sleeve I9 formed vwith internal splines or clutch teeth 20 in sliding splined engagement with splines 2| on the periphery of the hub member I3, and adapted to be shifted 40 axially by a shifting fork 22 to bring the splines 20 into positive clutching engagement with clutch teeth 23 formed on the torque transmitting member I0.. or clutch teethZI formed on the torque transmitting member I8. 45

Upon being moved into clutching engagement with the teeth 23, the sleeve I9 will receive rotation from the drive shaft I0 andvtransmit it directly through the hub I4 to the driven shaft I I. Upon being moved in the opposite direction 50 intoclutching engagement with the teeth 24. the

sleeve` I9 will receive rotation from the torque arrangement and therefore not illustrated) andy 66 A hub la 1S provided with internal splinesv l I will transmit such rotation through the hub member i4 to the driven shaft Il.

In order to synchronize a torque transmitting member I or I8 with the sleeve Il, preparatory l to establishing such positive clutching engagement, I provide a pair of synchronizer rings 2l, each including a substantially cylindrical collar portion 26 (see Fig. 4) rotatably mounted within the rim portion 21 of the hub I3, and a peripheral portion which is provided with blocker teeth 28 between which the splines 20 of the sleeve Il must pass before the clutching engagement with teeth 23 or 24 may be established. The opposed endsoftheteeth 2landofsplines 2|Imaybe Il chamfered, in accordance with well known practice. The rnchronizer rings 25 are provided with internal conical friction clutch faces 2l adapted to engage complementary external conical friction clutch faces l0 of friction clutch l0 elements 3l and 32, formed on the torque transmitting members i0 and Il respectively.

The hub i3 is I-shaped in cross section, including a hub proper Il, an annular radially extending web portion 34, and the rim portion 2l,

defining between them a pair of axially opening annular recesses 35 in which the collar portions 2l of the synchronizer rings are received.

The mounting of the synchroniser rings 2l within the rim of the hub It lssuch as toallow I0 them to move both circumrerenuauy and axiauy 4o commodated in axially extending slots 81' extend-- ing entirely through the rim 21 and` into the web Il. The thrust bars 38 are confined in the slots 31 against circumferential movement, but are free to slide longitudinally therein in paths parallel to 4,5 the axis of rotation of the torque transmitting members il and Ii. f

The thrust bars 36 may be of hollowstamped sheet metal construction, of the type illustrated in the joint application of myself and S.. O. White, Serial No. 250,908 filed January 14, 1939, for synchronizing transmission. They are formed, in, termediate their ends, with projections 3l, engageable in recesses 39 in the interior of the sleeve I9. and yieldingly urged into such engagement by expander rings 40 simultaneously engaging all of the bars. Thus a yleldable thrust receiving connection is established between the bars and the sleeve I9, so that when the sleeve is shifted axially, it will tend to carry the bars therewith. The axial thrust thus developed in the bars willbe transmitted to a synchronizer ring 25 through the abutting engagement of the giids of the bars with the end face of the collar In previous synchronizers of this general type, the synchrcnizer rings 2l have been provided, in the collar portion 28 thereof, with axially opening notches receiving the ends of the bars so as to form oscillatory lost motion'connections between the rings and the hub. In the present invention, the rings 2l are of full cross-sectional width throughout their circumferential extent, and the bars l0 are considerably shortened. so as to engage against the axial extremities of the shoulders 2l. An oscillatory lost motion conassumo:

nection between each ring 2l and the hub I2 is established through the medium of lugs Il formed v integrally with the ring and prjectlng radially outwardlyV from the collar portion 2l thereof, into the axial extremities of the slots I1. I It may now be noted that the slots 21 serve the dual purpose of forming slideways for the thrust` bars It, and cooperating with the lugs 4I to form lost motion connections between the synchronizer rings and the hub, the thrust bars l0 occupying the central regions of the slots and the lugs occupying the end regions of the slots'. The thrust bars are of sumcient width to substantially i111 the slots while'the lugs l4I are 'of considerably less width than the slots so as to il provide for the lost motion of the rings relative to the hub.

In the operation of a synchroniser embodying the invention, assuming the movable Jaw clutch sleve Il to be in a neutral position as shown in D 'Figure l, and thatl the operator desires to shift the tr into intermediatethe shifting fork 221s urged toward the right, viewing Figure 1, thereby urging the sleeve Il ltoward the right, and with it the three thrustbars 3l, through the 8l medium of the yieldable break away thrust transmitting connection I l, N. The ends ofthe bars, engaging a synchroniser ring 2l, will urge the latter into frictional clutching engagement with the friction clutch element l2 of the torque transu mitting member il. thus causingthe latter to approach the speed of rotation ofthe sleeve I2.

This frictional engagement of the synchroniser ring 2l will also be effective to cause the ring 2l to become biased ln'position blocking further i. travel of the sleeve i8 until, upon the completion of synchronization, the synchroniser ring will move back to a neutral position. allowing the splines 2l of the sleeve l0 to pass between the blocker teeth 2l and into positive clutching enu gagement with the teeth 24 of the torque transmitting element Il.

The invention has the advantage of providing a synchroniser which is relatively simple and inexpensive in construction, has a minimum num- .a ber of parts. is easytoassemble. is sure in operation, and is very durable.'

While I have described my invention in connection with certain speciflc embodiments thereof, it is to be understood that this is by way of 50 illustration and not by way of limitation and the scope of my invention is defined solely by the appended claims which should be construed as broadly as the prior art will permit. I

I claim: 55 a 1. In a transmission synchronizer. a torque transmitting member, a synchroniser ring shiftable axially for establishing a frictional driving connection between said member and a part to be synchronized therewith, an annular positive 60 drive element drivingly connected to said member, and shiftable axially for establishing a positive driving connection between said member and said part, said member having an axially extending slot, and a thrust bar sudsble in said not. arranged to receive thrust fromsaid positive drive element and to transmit such thrust to said ring, the latter having a lug projecting into said slot to form an oscillatory lost motion driving connection between the ring and said mem- 70 ber, and having blocking means adapted. in one position of said .lost motion connection'I to block .the pathV of axial advance' of said positive drive element until synchronization has been attained. 7l

2. In a tron synchroniser, atei-que@ transmittingmembenasynchroniserringadapted under axial pressme-.toestablisha synchronizing irictional driving connection between said s member and a part to'be synchronised therewith,

an annular positive drive element drlvingly connected to said member. and shiftable axially forv 'establishing a positive driving connection between said member and said part, said'member having in its peripheral region an axially extending slot, anda. thrust bar slidable in said slot, arranged to receive 'thrust from said positive drive element and to transmit such thru'st to said'ring, the latter having a lug proiectv ingintosaid siottotorinanoscillittorylostnrovtion driving connection between the ring and said member. and having blocking meam adapted, in one position o! said lostmotion'eonnection, to block .the path oi axial advance oi said U positive drive element until been attained.

3. In a tron a torque transmitting member, aeynchroniser ring adaptl ed under axial pressure to establish a synchroaxlally for establishing s positive driving conmember having an axially extending slot, and a thrust bar slidable in said slot. having a projection receivable in a corresponding recess in the interior o! said positive drive element so as to form a yieldable breakaway thrustreceiving connection therewith, and arranged to transmit to said ring the thrust thereby received, saidring having a lug projecting into said slot to form an,-

oscillatory lost m'otion driving connection be- 40 tween the ring and said member, and having blocking means adapted, in one position of said lost motion connection, to block the path of axial advance oi positive drive element untilsynchronization has been attained.

4. In a transmission synchroniser, a torque transmitting member, a synchroniser ring-ot uniform axial width throughout its circumferential extent adapted under axial pressure to establish a synchronizing irictional drivin connection between said member and a part to be synchronized therewith, an annular positive drive element drivingly connected to said member andv shiitable axially for establishing apontive driving connection betweenjsaid member and said part. said member having in its periphery an axially extending slot, a thrust bai' received in said slot, arranged to receive thrust from said positive drive element and having an end in abutting engagement with the inner radial face o! and a pair oi expander rings engaging'axislly spaced regions of said thrust bar and. m8 the same radially outwardly so as to establish said thrust receiving engagement, said ring hsving a llug projecting into said slot` to form an oscillatory lost motion driving connection between -the ring and said member, and having blocking'means adapted, in one position o! said lost motion connection, to block the path o! axial advance of said positive drive element until synchronization has been attained.

5. In a transmission synchroniser. a transmitting member including a radial web portion and a rim portion forming together withl 7s said web portion a pair oi opposed axially opennizing irictionai driving connection' between seid member and a part to be synchronised therewith, an annular positive 'drive element driv-v ingiy associated with said member. and shiitable r nection between said member and said part, said Y.

said ring so as to transmit such thrust thereto,`

torque i ing annular a pair of .opposed synchroniser rings oi uniform axial dimension throughout their circumferential extent. loosely moimted insaidrecessesandadaptedimderaxialpressure to establish synchronizing irictionai driving coni nectionbetweensaidmemberandaparttolsev therewith, an annular positive drive element encircling said member, drivingly connected thereto and shiftable axiallyro'r estab-` usmnz spenen drivin: connection between ma io memberandsaidparhsaidmemberhavingin .p its periphery a. plurality or axially extending.

spaced slots, a plurality of reltive slots. their eniisinabuttingthrustti'ens- 'v mittinsassociation withithe innerradiaitaees oftherespectiverlngaandtheirradiallyout-erl and a part to be synchronised therewith, an siinulsr positive drive element encircling said member, drivingly connected thereto and shiitable axially tor establishing a positive driving connection between said member and said part, said y member havingin its periphery a pluralitylo! axially extending. circumierentiaily spaced slots. apluralityoirelativeiyshortthrustbarsre` celved in the respective slots, their-ends in abutting thrust transmitting, association I inner radialy faces ot the respective their radially outerresions in association with said positive drive element', anexpanderrinsensasinsallor saidthrust barsandurgingthemradiallyoutwardlytbestablish clutch engagemenhfv y chronizer .as deiined im so mgrasiauycutwardiyrmmonencecfmacf lar portion, said rins bein! adapted under axial mmm s.

pressure to establish a driving connection between said member and part to be synchronized therewith, a movable jaw.

clutch sleeve encircling said member,

an'axially slot rim,rand a thrust bar slidable in s liiiiraivu'v l receivedintherespee-''v' connected thereto and mutable axially.'

ranged to receive thrust from said sleeve and to transmit such thrust to said ring, the latter having a lug projecting radially outwardly from said collar into said slot to form an oscillatory lost motion connection between the ring and said member, said blocking portion being adapted in one position of said lost motion connection to block the path of axial advance of said movable Jaw clutch sleeve until synchronization has been l0 attained. 

